Why is Middle America killing itself? The fact itself is probably the most important social science finding in years.

It is already reshaping American politics. The Washington Post's Jeff Guo notes that the people who make up this cohort are "largely responsible for Donald Trump's lead in the race for the Republican nomination for president." The key question is why, and exploring it provides answers that suggest that the rage dominating American politics will only get worse.

For decades, people in rich countries have lived longer lives. But in a now-famous paper, economists Angus Deaton and Anne Case find that over the last 15 years, one group, middle-aged whites in America, constitutes an alarming trend. They are dying in record numbers. And things look much worse for those with just a high school diploma or less.

There are some concerns about the calculations, but even the leading critic of the paper acknowledges that, however measured, "the change compared to other countries and groups is huge."

The main causes of death are as striking as the fact itself — suicide, alcoholism and overdoses of prescription and illegal drugs. "People seem to be killing themselves, slowly or quickly," Deaton told me. These circumstances are usually caused by stress, depression, and despair. The only comparable spike in deaths in an industrialized country took place among Russian males in the wake of the collapse of the Soviet Union, when rates of alcoholism skyrocketed.

A conventional explanation for this middle-class stress and anxiety is that globalization and technological change have placed increasing pressures on the average worker in an industrialized nation. But the trend is absent in any other Western country — it's an exclusively American phenomenon. And the United States is actually relatively insulated from the pressures of globalization, having a vast, self-contained internal market. Trade makes up only 23 percent of the American economy, compared with 71 percent in Germany and 45 percent in France.

Deaton speculated to me that perhaps Europe's more generous welfare state might ease some of the fears associated with the rapid change. Certainly he believes that in America, doctors and drug companies are far too eager to deal with physical and psychological pain by prescribing drugs, including powerful and addictive opioids. The timing of the introduction of drugs like Oxycontin, a heroin-like prescription painkiller, matches up with the start of the rise in death rates.

But what explains the fact that we don't see the trend in other American ethnic groups? While mortality rates for middle-aged whites have either stayed flat or risen, the rates for Hispanics and blacks have continued to decline significantly. These groups live in the same country and face greater economic pressures than whites. Why are they not in similar despair?

The answer might lie in expectations. Princeton anthropologist Carolyn Rouse suggested, in an email exchange, that other groups might not have the same expectations that their incomes, standard of living and social status were destined to improve steadily over time.

They don't have the same confidence that if they work hard, they would surely get ahead. In fact, Rouse said that after hundreds of years of slavery, segregation and racism, blacks have developed a set of ways to cope with disappointment and the unfairness of life — family, art, protest speech, and, above all, religion.

"You have been the veterans of creative suffering," Martin Luther King told African-Americans in his "I Have a Dream" speech in 1963: "Continue to work with the faith that unearned suffering is redemptive."

Writing in 1960, King explained the issue in personal terms: "As my sufferings mounted I soon realized that there were two ways that I could respond to my situation: either to react with bitterness or seek to transform the suffering into a creative force . . . So like the Apostle Paul I can now humbly but proudly say, 'I bear in my body the marks of the Lord Jesus.'"

The Hispanic and immigrant experience in America is different, of course. But again, few in these groups believed that their place in society was assured. Minorities, by definition, are on the margins. They do not assume that the system is set up for them. They try hard and hope to succeed, but they do not expect it as the norm.

America is going through a great power shift. Working-class whites don't think of themselves as an elite group. But, in a sense, they were, certainly compared with blacks, Hispanics, Native Americans and most immigrants.

They were central to America's economy, its society, indeed its very identity. They are not anymore. Donald Trump has promised that he will change this and make them win again. But he can't. No one can. And deep down, they know it.

Fareed Zakaria hosts CNN's "Fareed Zakaria GPS," and makes regular appearances on shows such as ABC's "This Week" and NBC's "Meet The Press." He has been an editor at large Time magazine since 2010, and spent 10 years overseeing Newsweek's foreign editions. He is a Washington Post (and internationally syndicated) columnist. He is author of: "The Post-American World." For more of Fareed Zakaria's reports, Go Here Now.